An invasive beetle, polyphagous shot hole borer (PSHB), has in other parts of the country resulted in more than 10 000 trees being lost, which could have an adverse effect on the ecosystem and take years to replace, according to reports quoting academic research.
The city’s Recreation and Parks Department and Invasive Species Uniplan have devised a plan to deal with the beetle species, known to invade the host tree and bore holes in the branches.
If undetected, it can destroy a tree within a relatively short period.
Mayoral committee member for community services and health, councillor Zahid Badroodien, warned that the damage the beetle could cause to trees should not be underestimated.
“Invasive species of this nature could go undetected, as people don’t usually inspect trees to see if there are any beetles.
“That is why it’s important that the City informs residents so that they can report sightings.
“The City has the responsibility to protect its trees, as they play an integral part in a healthy ecosystem and offer important environmental benefits,” he said.
PSHB beetles invade a variety of tree species, including oak, most willows, plane trees, avocado, some acacias and most maples, by digging tunnels to lay eggs.
They transport a fungus which attacks the tree’s vascular tissue. This causes a disease called fusarium dieback (FD) and interrupts the supply of water and nutrients to the tree.
The beetle attacks more than 300 tree species countrywide, of which more than 130 are susceptible to FD.
Metropolitan areas such as Johannesburg and Durban as well as Pietermaritzburg, George and Knysna have lost tens of thousands of trees.
“The city is working closely with the Forestry and Agricultural Biotechnology Institute of the University of Pretoria to ensure that the latest technology is shared, and to update databases for current and future research, in an effort to more effectively control the PSHB,” said Badroodien.
The host trees that are infected will clearly show visible symptoms of distress, including gum extraction on the bark entry and exit holes, sugary exudates and staining.
The City requests that the public report any sightings of the beetle by email to [email protected] or phone the toll-free number 0860 103089.